1. Field of the Invention
The present invention relates to aluminum-based alloys having a superior corrosion resistance together with a high degree of hardness, heat-resistance and wear-resistance, and which are useful in various industrial applications.
2. Description of the Prior Art
As conventional aluminum-based alloys, there are known pure aluminum type and multicomponent system alloys, such as Al-Mg system, Al-Cu system, Al-Mn system, or the like, and these known aluminum-based alloy materials have been used extensively in a variety of applications, for example, as structural component materials for aircraft, cars, ships or the like; outer building materials, sashes, roofs, etc.; structural component materials for marine apparatuses and nuclear reactors, etc., according to their properties.
However, these conventional alloy materials have difficulties in long services in corrosive environments.
Therefore, the present applicant has developed a corrosion-resistant material consisting of an amorphous aluminum alloy Al-M-Mo-Hf-Cr containing at least 50% by volume of an amorphous phase, wherein M is one or more metal elements selected from Ni, Fe and Co. (refer to Japanese Patent Application No. 2-51 823).
However, there are difficulties in the preparation of the above amorphous alloys. That is, when the alloy is made amorphous, the amounts of Cr, which has the effect of improving the corrosion resistance, tend to be restricted depending on the amounts of Hf, which improves the above ability to form an amorphous phase. When Cr is added in amounts exceeding a certain amount of Hf, crystallization tends to occur in part and thereby the corrosion resistance of the thus partially crystallized alloy will become low as compared with that of entirely amorphous alloys. As a further problem, when Hf is added in large amounts, the resulting alloys become expensive, because Hf is the most expensive element among the above-mentioned elements.